Airborne particles may irritate e.g. eyes and mucous membranes. The smaller the particles, the greater problems may potentially be caused, as transportation of particles, via the airways into the lungs, and further into the blood stream, is facilitated with reduced particle size.
Ionic air purification is increasingly used indoors. Such air purification utilizes the principle of positively charge particles being attracted by negatively charged surfaces and vice versa. Hence, if an voltage is applied between a first, preferably pointy, emitter electrode and a second plate electrode, the second plate electrode may serve as a collector of charged particles.
If the difference in electric potential between the two electrodes is sufficiently large, the intermediate air will be excited by an electromagnetic, EM, field, such that intermediate airborne particles may become ionized, and subsequently deposit, or precipitate, on the second plate electrode.
U.S. Pat. No. 7,806,952 discloses an air purifier device comprising an ionizing system. The ionizing system is placed within an air outlet of the air purifier device, and comprises a high voltage electrode arranged on a distal end protruding from a portion of a fan housing. An alternating voltage field is generated from the first electrode and causes ionized particles to deposit on the housing by bleeding accumulated charge to a lower potential bleeding electrode arranged around the air outlet. Bleeding of the charge is possible because the housing has certain conductive properties, i.e. it is not a perfect insulator. The bleeding electrode has a significant surface area in order to discharge the excessive charges. The high voltage electrode is arranged close to the center of the opening, so as to create a voltage field across the entire opening of the outlet.
This air purification principle is sometimes referred to as electrostatic precipitation, ESP, or electrostatic cleaning. The principle is usually effective only within short range from the collector.